Earthquake! Student Materials

STUDENT

WHAT'S THIS PROJECT ABOUT AND WHY DOES IT MATTER?

Many engineers are involved in the design of structures of one type or another. Designing structures requires that the engineer knows what kind of loads will be (or even might be!) experienced by the structure. The engineer must also have a good understanding of the properties of (and limitations of) different structural elements and structural materials in order to use them effectively.

Earthquakes can produce some of the most severe loads that fixed structures experience. In this project, the effects of earthquakes on structures will be simulated by shaking the foundation on which the structures are mounted. A concentrated mass will be supported in an elevated position using a limited quantity of low strength material, and the inertia of the mass will cause sideways loads, and perhaps damage to the structure.

WHAT ARE WE SUPPOSED TO DO?

You will design and build a structure to support one unbroken raw egg (to be provided) 18 inches above a 12 inch by 12 inch thin plywood base to which the structure is to be permanently attached. Your goal is to design the strongest structure possible by using the available material wisely. This kind of challenge is typical of those involved in many practical engineering problems.

WHAT EQUIPMENT AND MATERIALS CAN WE USE?

Materials are limited to 3 sheets of standard 8 1/2 by 11 copier paper, 2 feet of common cellophane tape, six rubber bands and of course the plywood base. Taping around the edge and onto the bottom of the base is OK. Your instructor will provide a wooden pallet with ropes attached to simulate the earthquake. Small C-clamps will be used to attach the individual structures to the pallet for testing.

HOW WILL WE KNOW HOW WELL WE HAVE SUCCEEDED?

The basic performance requirement is to just support the egg 18 inches high without any motion applied to the base. To determine superior performance the projects will be tested in groups all attached to the same pallet and experiencing the same "earthquake" which will gradually increase in intensity. The best structures will survive the longest!

WHAT ELSE WOULD BE USEFUL TO KNOW?

Sheet materials (like paper) work well in tension (pulling) but not so well in compression (pushing). Paper can be rolled up or folded so that it behaves better in compression, but even a narrow strip of paper works efficiently in tension. Real structures often have different parts which experience different kinds of loads. Some of these loads you can figure out yourself just using common sense. Try to use your 3 sheets of paper with these ideas in mind.

HAVE FUN!

Engineers do.